This invention relates to an automatic control system for raising and lowering the header of a combine.
The combine header mounted on the front of a combine is usually moveably mounted so that a hydraulic cylinder or cylinders can be used to raise and lower the header as desired. The header includes a cutter bar which is positioned in close proximity to the ground. Various automatic control systems have been provided for causing the header to be raised and lowered in response to variations in the terrain of the ground. This permits the cutter bar to remain in close proximity to the ground without cutting into it or becoming buried in the ground.
Presently known devices for automatically controlling the height of the combine header generally include a linkage which is connected to the cutter bar at one end and which is connected to a hydraulic valve at the other end. As the cutter bar moves upwardly and downwardly the linkage causes movement of the hydraulic valve. The hydraulic valve is connected in a system with the cylinders for raising and lowering the combine header. Thus the hydraulic valve causes the hydraulic cylinders to raise and lower the combine header in response to the raising and lowering of the cutter bar.
This type of automatic control system has proved disadvantageous in that it is not adequately sensitive to changes in the terrain. Oftentimes the cutter bar becomes buried in the ground when the header encounters a rise or lump in the terrain. Furthermore, when the terrain includes a depression the cutter bar often is not dropped quickly enough. The result is that the particular crop being harvested is cut at a height much higher on the plant than is desirable. For example in the harvesting of soybeans, the cutter bars oftentimes will cut off the soybeans at a height above the lowermost pods on the stalk.
Therefore, a primary object of the present invention is the provision of an improved automatic control system for controlling the height of a combine header.
A further object of the present invention is the provision of a control system which provides quick and positive response to slight variations in the terrain over which the combine header is moving.
A further object of the present invention is the provision of an automatic control system which can be easily adapted with simple modification of the control systems presently used on combine headers.
Another object of the present invention is the provision of an automatic control device which permits easy adjustment of the sensitivity of the device to variations in the terrain.
A further object of the present invention is the provision of an automatic control device system which acts more quickly, is more accurate, and is easier to adjust than prior devices.
A further object of the present invention is the provision of a control device which permits the header to be removed and reinstalled without having to readjust any valve system.
A further object of the present invention is the provision of a device which can be utilized with and is compatible with the hydraulic systems and the electrical systems presently found on conventional combines.
A further object of the present invention is the provision of a device which is economical to manufacture, durable in use, and efficient in operation.